1. Field of the Invention
Disclosed embodiments relate to a radar apparatus and a target detecting method.
2. Description of the Related Art
In the related art, there was known a radar apparatus that has an array antenna, estimates an arrival direction of a reflection wave by analyzing the reflection wave received by using the array antenna, and detects a landmark based on the estimated arrival direction (see, for example, Japanese Patent Application Laid-Open No. 2004-108851).
The radar apparatus is used for, for example, a vehicle following system that is mounted on a vehicle and follows an own car to a leading car while detecting the leading car which is precedent to the own car as a landmark (hereinafter, referred to as a “target”) which becomes the target on a traffic lane on which the own car travels.
Further, at the time of estimating the arrival direction of the reflection wave as described above, a so called beam scanning type BF (beam forming) method or a method called a null scanning type ESPRIT (estimation of signal parameters via rotational invariance techniques) was generally known.
However, when the related art is used, there was a problem in that false detection of the target easily occurs in the case where a strong reflection-level target (hereinafter, referred to as a “strong reflection object”) exists around the target.
For example, when the leading car travels between a large vehicle such as a truck, or a bus which easily becomes the strong reflection object, a reflection wave from the large vehicle largely interferes in a reflection wave from the leading car, and as a result, it was difficult to detect whether there is the leading car.
From this point of view, it becomes a large task how to realize a radar apparatus or a target detecting method that can detect the target with high precision.